This Sunday’s massive, five-borough road race is expected to bring the largest economic windfall to the city of any sporting event ever, as New York’s economy will run green with some $350 million in marathon-related activity, Mayor Bloomberg announced yesterday

The 26.2-mile competition — which will attract more than 47,000 runners, many out-of-towners bringing in scads of cash — will also generate more than $10 million in tax revenue, the mayor estimated.

“It’s one of those events that really does set us apart,” said Bloomberg before painting the orange and blue finish line in Central Park. “The race is a major boon to our economy.”

Runners from all 50 states and an estimated 135 countries will tackle the five boroughs. More than 2 million people are expected to watch live this weekend.

There are nearly 2,000 more runners in the race this year over last year. Also, many of the visitors will stay for at least a week and spend money.

“There’s something truly magical about marathon Sunday, the miles and miles of cheering spectators, the thrill of the race and the inspiring stories of the participants, the incredible hard work of thousands of volunteers who help make everything tick,” Bloomberg gushed.

“This is a race that really brings the city together in a unique way.”

The mayor routinely greets runners at the start on the Verrazano-Narrows Bridge in Staten Island and again at the finish line.

Cleanup crews were scurrying around Central Park yesterday, picking up debris that had fallen during the surprise snowstorm over the weekend. Bloomberg said the blizzard caused the worst damage Central Park has seen in 30 years.

Had the storm hit this weekend, the entire marathon route would have been changed and the finish line would have been moved, city Parks Commissioner Adrian Benepe said.

“By this weekend the park will be back to normal, just in time for us to enjoy one of the greatest moments in the world,” Bloomberg said.

The runners participating in the 42nd annual race are likely to have perfect running weather.

Weather.com is predicting a forecast of 55 degrees and sunny for Sunday.